Preheat oven to 325°F. Fill pan with cupcake liners.
In a large bowl, whisk together eggs, vegetable oil, and water until smooth.
Add in the Chocolate Lovers Brownie Mix and stir until combined. Spoon the mix into each cupcake tin, about 3/4 full.
Bake for 26-28 minutes, or until toothpick inserted in middle comes clean.
While cupcakes are baking and cooling, prepare the frosting. Cream together the butter and peanut butter in a mixer on high speed until smooth.
Slowly add in the Vanilla Frosting Mix and milk. Whip on medium high speed until smooth.
When cupcakes are cool, pipe the peanut butter frosting on the chocolate cupcakes. Serve with a large glass of milk and enjoy!